Water-Resistant Exterior Joint Compounds

ABSTRACT

Embodiments of the present disclosure are directed to joint compounds for sealing exterior sheathing wallboards applied on the exterior of buildings. This invention also relates to a process of preparing such exterior joint compounds. The joint compounds of this invention comprise an aqueous emulsion system and provide water resistance comparable to the substrate on which they are applied, that is, the exterior sheathing wallboards.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.16/401,622 filed May 2, 2019 which is a continuation of U.S. applicationSer. No. 15/944,132 filed Apr. 3, 2018 now Pat. No. 10,281,558, issuedMay 7, 2019, which is a continuation of U.S. application Ser. No.15/804,024 filed Nov. 6, 2017 now Pat. No. 9,964,628 issued May 8, 2018,which is a divisional of U.S. application Ser. No. 14/923,772 filed Oct.27, 2015 now Pat. No. 9,834,680 issued Dec. 5, 2017, which claimsbenefit of U.S. Provisional Patent Application No. 62/069,124, filedOct. 27, 2014, each of which is hereby incorporated by reference in itsentirety.

TECHNICAL FIELD

This invention relates to joint compounds for sealing exterior sheathingwallboards applied on the exterior of buildings. This invention alsorelates to a process of preparing such exterior joint compounds. Thejoint compounds of this invention comprise an aqueous emulsion systemand provide water resistance comparable to the substrate on which theyare applied, that is, the exterior sheathing wallboards.

BACKGROUND

Modern techniques for constructing building walls include, for example,the two-by-four (2×4) framed construction, comprising wood or metal(such as, steel) members. These 2×4s are oriented vertically andconnected at the top and bottom to similar members that are horizontallyoriented. This structure is referred to in the relevant art as a“framed” wall. A sheet of building wall substrate or exterior sheathingwallboard, such as plywood sheathing, specially formulated gypsumwallboards, cement panels, or fiber cement panels are affixed tobuilding frame.

A water-resistive barrier is then typically applied to the exterior ofthe sheathing wallboard, with an external wall cladding or finish thenbeing applied directly over the water-resistive barrier. Many materialsmay be used for the external wall finish such as brick, stucco, vinyl oraluminum siding, and/or wood. For example, stucco exterior finishes makeup one of the most common ways of finishing exteriors of both residencesand commercial buildings. Stucco finishes have limitations including,porosity, rigidity, freeze/thaw fractures, fungal and mildew formation,cracking, and compromised weatherability if not applied properly.However, because modern exterior finishes are watertight, any water thatremains trapped behind these finishes does not readily evaporate. Thetrapped water behind the exterior finish can then soak into thesubstrata, for example, the sheathing wallboard and framing of thebuilding. The water that soaks into the substrata and framing oftencauses severe damage to the building without any signs of damageappearing on the exterior of the building. These problems can existregardless of the age of the building or the quality of construction.

The exterior sheathing wallboards such as gypsum (or other) wall-boardsused as structures, are joined at edges by joint compounds. Duringconstruction, these exterior sheathing wallboards are exposed to outsideenvironment, which, compared to the interior environment of a buildingis rather severe. The exterior sheathing wallboards are exposed to UV,rain, wind, heat, cold, and other physically abrasive impactors such asdebris, insects and birds, particularly during construction work. Thus,these boards are specially formulated to have weatherability andparticularly water resistance of 100 g/m² or lower 2-hour waterpermeance or Cobb value. Just like interior drywall panels, exteriorsheathing wallboard panels, when installed, have seams or joints betweeneach panel that must be filled so that a smooth exterior finish may beapplied. The joints between these exterior wall-boards or sheathing,therefore, become the weak link from where moisture can penetratethrough the walls of the building and into the interior. Currently, thejoint compound (or the water resistive barrier) used to seal the jointsbetween the sheathing and to provide water resistance include asilyl-terminated-polyether (STPE) flashing membrane system. The Cobbvalue of such STPE systems is around 2 g/m². Stated another way, thejoint compound or the sealant that is currently used is about thirtytimes more water resistant than the gypsum wall-boards having the muchlarger exposed area. The STPE based systems are not water based andtherefore have inherent issues relating to dealing with organic chemicalsolvents. Also, these are very expensive systems.

For the exterior or the interior wallboards, to achieve a smooth,visually appealing surface, the joints between boards, cracks, screwholes, and/or nail holes must be concealed. Conventional wallboard jointcompounds for the interior are used to cover and finish gypsum wallboardjoints, cornerbead, and screw or nail holes. Joint compounds can bespread over mesh or tape used to connect wallboards. It may also be usedto patch and texture interior walls. The intrusion of water through wallspaces, either through prolonged direct contact or via high humidity,has a debilitating effect (mold and structural damage) on standard wallsystems. The result of water seepage through joint compound to the studson the other side of the wall ultimately has devastating structural andmicrobial implications for the wall system, first by absorption of theseeped water into the wood studs followed by their swelling anddeformation (leading to expensive structural problems) and then, thecreation of a fertile ground for rapid mold growth.

Some performance requirements of exterior sheathing wallboards include(1) long-term weather-resistance; (2) mold resistance; and (3) waterresistance. These performance characteristics are quite stringent, andit is to be expected that whichever material that is to be used to coverthe joints between these sheathing boards (as well as the nail heads)should, at a minimum, display the same performance characteristics asthat of the corresponding sheathing wallboards. It is problematicachieving all of these characteristics, especially water and weatherresistance with a water-based system. This is because a water basedsystem would have a higher propensity to degrade or be washed away withtime. It is for this reason that the joint fillers for exteriorsheathing boards have largely been non-water based materials such assilyl-terminated polyethers. Where water based formulations have beenused, they have had to be very high in latex content and correspondinglylow in water content. Formulations that are high in organic polymercontent (such as STPE and water based acrylic latexes) invariably comewith handling difficulties such as poor washability and undesirableodors. This invention addresses the above problems and relates to anexterior joint compound that has a significantly lower acrylic latexcontent, yet displays exceptional water, weather, and mold resistance.This inventive joint compound contains a specially formulated waxemulsion designed to impart exceptional water repellency to coatingsformulations. Particularly, the invention relates to exterior jointcompounds that are water-based but with water repellant andanti-microbial character. Because the exterior of a building especiallyduring construction is exposed to sever weather conditions such as rainand moisture, it is counterintuitive to envision using a water-basedsystem that can handle the harshness of the exterior environmentespecially when such joints serve as the weak link for moisture entry.Wax emulsions have been used in composite wallboard (e.g., gypsumwallboard) for many years for the interior in the building industry. Forexample, wax emulsions sold under the trade name AQUALITE® by HenryCompany, and several wax emulsion formulations are disclosed in theprior art, such as U.S. Pat. No. 5,437,722. However, wax emulsions havenot been used in exterior joint compounds. The inventors of thisinvention have arrived at a water based formulation that includeswax-based emulsion systems as one component to be used a joint compoundbetween the exterior sheathing wallboard panels.

SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

Disclosed herein is a water-resistant exterior joint compound which cancomprise water, preservative, and wax emulsion, or silicone, orsiliconate, or fluorinated compound, or stearate, or combinationsthereof. In some embodiments, the exterior joint compound furthercomprises a rheology modifier, a binder, a thickener, and a filler. Insome other embodiments of the invention the joint compound furthercomprises calcium carbonate, or cristobalite, or gypsum, or mica, orclay, or thickener, or a latex binder, or talc, or perlite, or expandedperlite, or combinations thereof. In yet another set of embodiments,this invention relates to an exterior joint compound that furthercomprises calcium carbonate, or a micro-roughened filler, or gypsum, ormica, or clay, or thickener, or a latex binder, or talc, or perlite, orexpanded perlite, or combinations thereof.

In some embodiments, the above-referenced exterior joint compounds aresuch that the wax emulsion is configured to increase water-repellency ofthe joint compound.

In some embodiments of the invention the thickener comprises celluloseether.

In some embodiment, the exterior joint compound further comprises:

-   -   about 15 to about 40 wt. % water;    -   about 0.1 to about 1.0 wt. % preservatives;    -   about 10 to about 50 wt. % calcium carbonate;    -   about 0.0 to about 20% mica;    -   about 0.0 to about 3 wt. % attapulgite clay;    -   about 0.0 to about 15 wt. % expanded perlite;    -   about 15.0 to about 40.0 wt. % wax emulsion;    -   about 1.0 to about 10 wt. % latex binder;    -   about 0.0 to 5.0% siliconate;    -   about 0.0 to 0.1 wt. % and    -   about 0.1 to about 3.0 wt. % cellulose ether thickener.

In some embodiments, the exterior joint compound described above has thewax emulsion that comprises:

-   -   water;    -   polyvinyl alcohol;    -   paraffin wax;    -   a base;    -   a dispersant; and    -   montan wax.

In some embodiments, the base in the wax emulsion is diethanolamine,triethanolamine, an alkali metal hydroxide, or potassium siliconate. Insome other embodiments the dispersant is lignosulfonate. In yet otherembodiments the wax emulsion comprises paraffin wax, or montan wax, orcarnauba wax, or sunflower wax, or rice wax, or tallow wax, or a waxcontaining organic acids and/or esters, or an emulsifier containing amixture of organic acids such as stearic acid and/or esters, orsynthetic wax or combinations thereof.

In some embodiments, the wax emulsion is stabilized with polyvinylalcohol. In some other embodiments, the joint compound has a pH below 9.In yet other embodiments, the exterior joint compound has a contactangle of about 60 to about 110 degrees. In some embodiments, the jointcompound has a Cobb value of about 5.0 to about 100 grams per squaremeter.

In some embodiment, the exterior joint compound comprises a waxemulsion; and silicones, or siliconates, or fluorinated compounds, orstearates, or combinations thereof. In some embodiments, such silicones,siliconates, fluorinated compounds, or stearates are selected from thegroup consisting of metal siliconate salts, potassium siliconate, polyhydrogen methyl siloxane, polydimethyl siloxane, stearate-based salts,and combinations thereof.

This invention also relates to a method of applying water-resistantexterior joint compounds described above, comprising the steps of:

mixing a combination of:

-   -   water;    -   preservative; and    -   wax emulsion, or silicone, or siliconate, or a fluorinated        compound, or stearate, or combinations thereof to form a        water-resistant joint compound; and

applying the water-resistant joint compound to an exterior sheathingwallboard.

DETAILED DESCRIPTION

Embodiments of the present disclosure provide a water-resistant exteriorjoint compound formed from a wax emulsion. The joint compound mayoptionally be used to create a water resistant barrier at exterior walljoints, as well as at holes, such as nail holes, through a wall, therebypreventing moisture from passing through the walls. The joint compoundmay optionally be used, for example, in construction of houses orcommercial buildings. The joint compound can contain, in someembodiments, a montan activated and polyvinyl alcohol stabilized waxemulsion. By doing so, the resulting dried joint compound surface canexhibit a high contact angle, which can lead to exceptional waterrepellency. Further, the disclosed joint compound formed from a waxemulsion can avoid deleterious effects on key desirable performanceproperties of the joint compound.

By “microbe mitigating”, it is meant that applying the exterior jointcompound comprising one or more biocides reduces a microbe population bydirect cidal action, by substantial arrest of cell division or cellularrespiration and/or any other mechanism of action; reduces the rate ofproliferation of a microbe population; and/or substantially prevents theestablishment of a microbe population on a surface to which the barrieror emulsion is applied; as compared to the same activity(ies) or asurface that does not bear the emulsion or barrier of the invention.

By “microbe” it is meant any of one or more prokaryotic or eukaryoticsingle or multi-celled organisms, including, for example, bacteria,molds, lichens, algae, organisms of kingdom fungi (including yeasts),organisms conventionally regarded as protists, organisms of the kingdomformerly known as Monera, viruses, and amoebae. By “effective amount,”it is meant an amount sufficient to prevent, eliminate, and/or reducegrowth of a microbe population on a surface.

The joint compound can be used to create a moisture resistant jointcompound that can, for example, complement and be used on moistureresistant gypsum boards specially formulated for the exteriorenvironment during construction. These boards, along with the jointcompound, can be used in moisture situations, for example during rain orhigh humidity exposure of exterior sheathing. The use of the moistureresistant boards and joint compounds can help to reduce thesusceptibility of the walls, and the studs behind the walls, to moldgrowth and structural deformation caused through the absorption ofwater, reducing damage and health risks.

The terms “approximately”, “about”, and “substantially” as used hereinrepresent an amount close to the stated amount that still performs adesired function or achieves a desired result. For example, the terms“approximately”, “about”, and “substantially” may refer to an amountthat is within less than 10% of, within less than 5% of, within lessthan 1% of, within less than 0.1% of, and within less than 0.01% of thestated amount.

Certain example embodiments of the joint compound can be generallyprepared from an improved wax emulsion, among other materials andadditives. More details on example embodiments of the differentmaterials are disclosed herein.

Wax Emulsions Including Moisture Resistant Stabilizers

Embodiments of an improved wax emulsion for use in a water-resistantexterior joint compound are now described in greater detail, as follows.An embodiment of the wax emulsion comprises water, a base, at least onewax selected from slack wax, montan wax, and paraffin wax, and apolymeric stabilizer, such as ethylene-vinyl alcohol-vinyl acetateterpolymer or polyvinyl alcohol. Further, carnauba wax, sunflower wax,tall oil, tallow wax, rice wax, and any other natural or synthetic waxor emulsifier containing organic acids and/or esters can be used to formthe wax emulsion.

Waxes

Waxes described herein can be used in the present invention. For thepurposes of some embodiments of the present invention, waxes includenaturally occurring waxes and synthetic waxes. Naturally occurring waxesinclude plant based waxes, animal based waxes, and mineral waxes.Synthetic waxes are made by physical or chemical processes.

Examples of plant based waxes include mixtures of unesterifiedhydrocarbons, which may predominate over esters. The epicuticular waxesof plants are mixtures of substituted long-chain aliphatic hydrocarbons,containing alkanes, alkyl esters, sterol esters, fatty acids, primaryand secondary alcohols, diols, ketones, aldehydes, aliphatic aldehydes,primary and secondary alcohols, β-diketones, triacylglycerols, and manymore. The nature of the other lipid constituents can vary greatly withthe source of the waxy material, but they include hydrocarbons, Plantleaf surfaces are coated with a thin layer of waxy material. Specificexamples of plant wax include Carnauba wax, which is a hard wax obtainedfrom the Brazilian palm Copernicia prunifera, which contains the estermyricyl cerotate. Other plant based waxes include candelilla wax,ouricury wax, jojoba plant wax, bayberry wax, Japan wax, sunflower wax,tall oil, tallow wax, rice wax, and tallows.

Animal wax includes beeswax as well as waxes secreted by other insects.A major component of the beeswax used in constructing honeycombs is theester myricyl palmitate which is an ester of triacontanol and palmiticacid. Spermaceti occurs in large amounts in the head oil of the spermwhale. One of its main constituents is cetyl palmitate, another ester ofa fatty acid and a fatty alcohol. Lanolin is a wax obtained from wool,consisting of esters of sterols. Other animal wax examples includelanocerin, shellac, and ozokerite.

Examples of mineral waxes include montan wax, paraffin wax,microcrystalline wax and intermediate wax. Although many natural waxescontain esters, paraffin waxes are hydrocarbons, mixtures of alkanesusually in a homologous series of chain lengths. Paraffin waxes aremixtures of saturated n- and iso-alkanes, naphthenes, and alkyl- andnaphthene-substituted aromatic compounds. The degree of branching has animportant influence on the properties. Montan wax is a fossilized waxextracted from coal and lignite. It is very hard, reflecting the highconcentration of saturated fatty acids/esters and alcohols. Montan waxincludes chemical components formed of long chain alkyl acids and alkylesters having chain lengths of about 24 to 30 carbons. In addition,natural montan includes resin acids, polyterpenes and some alcohol,ketone and other hydrocarbons such that it is not a “pure” wax. Thesaponification number of montan, which is a saponifiable wax, is about92 and its melting point is about 80° C. In addition to montan wax,other naturally derived waxes are known for use in various industriesand include petroleum waxes derived from crude oil after processing,which include macrocrystalline wax, microcrystalline wax, petrolatum andparaffin wax. Paraffin wax is also a natural wax derived from petroleumand formed principally of straight-chain alkanes having average chainlengths of 20-30 carbon atoms.

Synthetic waxes include waxes based on polypropylene, polyethylene, andpolytetrafluoroethylene. Other synthetic waxes are based on fatty acidamines, Fischer Tropsch, and polyamides. Polyethylene and relatedderivatives. Some waxes are obtained by cracking polyethylene at 400° C.The products have the formula (CH₂)_(n)H₂, where n ranges between about50 and 100.

Also outside of the building products context, in addition to waxes thatoccur in natural form, there are various known synthetic waxes whichinclude synthetic polyethylene wax of low molecular weight, i.e.,molecular weights of less than about 10,000, and polyethylenes that havewax-like properties. Such waxes can be formed by direct polymerizationof ethylene under conditions suitable to control molecular weight.Polyethylenes with molecular weights in about the 2,000-4,000 range arewaxes, and when in the range of about 4,000-12,000 become wax resins.

Fischer-Tropsch waxes are polymethylene waxes produced by a particularpolymerization synthesis, specifically, a Fischer-Tropsch synthesis(polymerization of carbon monoxide under high pressure, high temperatureand special catalysts to produce hydrocarbon, followed by distillationto separate the products into liquid fuels and waxes). Such waxes(hydrocarbon waxes of microcrystalline, polyethylene and polymethylenetypes) can be chemically modified by, e.g., air oxidation (to give anacid number of 30 or less and a saponification number no lower than 25)or modified with maleic anhydride or carboxylic acid. Such modifiedwaxes are more easily emulsified in water and can be saponified oresterified. Other known synthetic waxes are polymerized alpha-olefins.These are waxes formed of higher alpha-olefins of 20 or more carbonatoms that have wax like properties. The materials are very branchedwith broad molecular weight distributions and melting points rangingabout 54° C. to 75° C. with molecular weights of about 2,600 to 2,800.Thus, waxes differ depending on the nature of the base material as wellas the polymerization or synthesis process, and resulting chemicalstructure, including the use and type of any chemical modification.

Various types of alpha-olefin and other olefinic synthetic waxes areknown within the broad category of waxes, as are chemically modifiedwaxes, and have been used in a variety of applications, outside thewater-resistant wallboard area. They are of a wide variety and vary incontent and chemical structure. As noted above, water-resistantwallboard products generally use paraffin, paraffin and montan, or otherparaffinic or synthetic waxes as described above in the mentionedexemplary patent references. While various waxes and wax substituteshave been used and tried in the building products area for wax emulsionsgenerally, particularly in some cases with a goal toward finding anadequate substitute for use of montan wax, the waxes as have beenadopted to date do not include normal alpha-olefin or oxidizedalpha-olefin waxes.

Water may be provided to the emulsion, for example in amounts of about30% to about 60% by weight of the emulsion. The solids content of thewax emulsion is preferably about 40% to about 70% by weight of theemulsion. Other amounts may be used.

In some embodiments, a dispersant and/or a surfactant may be employed inthe improved wax emulsions. Optional dispersants, include, but are notlimited to those having a sulfur or a sulfur-containing group(s) in thecompound such as sulfonic acids (R—S(═O)₂—OH) and their salts, whereinthe R groups may be otherwise functionalized with hydroxyl, carboxyl orother useful bonding groups. In some embodiments, higher molecularweight sulfonic acid compounds such as lignosulfonate, lignosulfonicacid, and naphthalene sulfonic acid, sulfonate salts of these acids andderivatized or functionalized versions of these materials are used inaddition or instead. An example lignosulfonic acid salt is Polyfon® Havailable from MeadWestvaco Corporation, Charleston, S.C. Otherdispersants may be used, such as magnesium sulfate, polycarboxylatetechnology, ammonium hepta molybdate/starch combinations, non-ionicsurfactants, ionic surfactants, zwitterionic surfactants and mixturesthereof, alkyl quaternary ammonium montmorillonite clay, etc. Similarmaterials may also be used, where such materials may be compatible withand perform well with the formulation components. The wax component ofthe emulsion may include at least one wax which may be slack wax, montanwax and/or slack wax. The total wax content may be about 30% to about60%, more preferably about 30% to about 40% by weight of the emulsion.Slack wax may be any suitable slack wax known or to be developed whichincorporates a material that is a higher petroleum refining fraction ofgenerally up to about 20% by weight oil. In addition to, or as analternative to slack wax, paraffin waxes of a more refined fraction arealso useful within the scope of the invention.

Suitable paraffin waxes may be any suitable paraffin wax, and preferablyparaffins of melting points of from about 40° C. to about 110° C.,although lower or higher melting points may be used if drying conditionsare altered accordingly using any techniques known or yet to bedeveloped in the composite board manufacturing arts or otherwise. Thus,petroleum fraction waxes, either paraffin or microcrystalline, and whichmay be either in the form of varying levels of refined paraffins, orless refined slack wax may be used. Optionally, synthetic waxes such asethylenic polymers or hydrocarbon types derived via Fischer-Tropschsynthesis may be included in addition or instead, however paraffins orslack waxes are preferred in certain embodiments. Montan wax, which isalso known in the art as lignite wax, is a hard, naturally occurring waxthat is typically dark to amber in color (although lighter, more refinedmontan waxes are also commercially available). Montan is insoluble inwater, but is soluble in solvents such as carbon tetrachloride, benzeneand chloroform. In addition to naturally derived montan wax, alkyl acidsand/or alkyl esters which are derived from high molecular weight fattyacids of synthetic or natural sources with chain lengths preferably ofover 18 carbons, more preferably from 26 to 46 carbons that function ina manner similar to naturally derived montan wax are also within thescope of the invention and are included within the scope of “montan wax”as that term is used herein unless the context indicates otherwise(e.g., “naturally occurring montan wax”). Such alkyl acids are generallydescribed as being of formula R—COOH, where R is an alkyl non-polargroup which is lipophilic and can be from 18 to more than 200 carbons.An example of such a material is octacosanoic acid and its correspondingester which is, for example, a di-ester of that acid with ethyleneglycol. The COOH group forms hydrophilic polar salts in the presence ofalkali metals such as sodium or potassium in the emulsion. While thealkyl portion of the molecule gets embedded within the paraffin, theacid portion is at the paraffin/aqueous medium interface, providingstability to the emulsion. Other components which may be added includeesterified products of the alkyl acids with alcohols or glycols.

In some embodiments, the at least one wax component of the emulsionincludes primarily and, preferably completely a slack wax component. Insome embodiments, the at least one wax component is made up of acombination of paraffin wax and montan wax or of slack wax and montanwax. Although it should be understood that varying combinations of suchwaxes can be used. When using montan wax in combination with one or moreof the other suitable wax components, it is preferred that montan bepresent in an amount of about 0.1% to about 10%, more preferably about1% to about 4% by weight of the wax emulsion with the remaining wax orwaxes present in amounts of from about 30% to about 50%, more preferablyabout 30% to about 35% by weight of the wax emulsion.

In some embodiments, the wax emulsion includes polyvinyl alcohol (PVOH)of any suitable grade which is at least partially hydrolyzed. Thepreferred polyvinyl alcohol is at least 80%, and more preferably atleast 90%, and most preferably about 97-100% hydrolyzed polyvinylacetate. Suitably, the polyvinyl alcohol is soluble in water at elevatedtemperatures of about 60° C. to about 95° C., but insoluble in coldwater. The hydrolyzed polyvinyl alcohol is preferably included in theemulsion in an amount of up to about 5% by weight, preferably 0.1% toabout 5% by weight of the emulsion, and most preferably about 2% toabout 3% by weight of the wax emulsion.

In some embodiments, the stabilizer comprises a polymer that is capableof hydrogen bonding to the carboxylate or similar moieties at thewater/paraffin interface. Polymers that fit the hydrogen-bondingrequirement would have such groups as hydroxyl, amine, and/or thiol,amongst others, along the polymer chain. Reducing the polymer's affinityfor water (and thus, its water solubility) could be achieved byinserting hydrophobic groups such as alkyl, alkoxy silanes, or alkylhalide groups into the polymer chain. The result may be a polymer suchas ethylene-vinyl acetate-vinyl alcohol terpolymer (where the vinylacetate has been substantially hydrolyzed). The vinyl acetate contentmay be between 0% to 15%. In some embodiments, the vinyl acetate contentis between 0% and 3% of the terpolymer chain. The ethylene-vinylalcohol-vinyl acetate terpolymer may be included in the emulsion in anamount of up to about 10.0% by weight, preferably 0.1% to about 5.0% byweight of the emulsion. In some embodiments, ethylene-vinylalcohol-vinyl acetate terpolymer may be included in the emulsion in anamount of about 2% to about 3% by weight of the wax emulsion. An exampleethylene-vinyl alcohol-vinyl acetate terpolymer that is available is theExceval AQ4104™, available from Kuraray Chemical Company.

The wax emulsion may include a stabilizer material (e.g., PVOH,ethylene-vinyl alcohol-vinyl acetate terpolymer as described above). Thestabilizer may be soluble in water at elevated temperatures similar tothose disclosed with reference to PVOH (e.g., about 60° C. up to about95° C.), but insoluble in cold water. The active species in the waxcomponent (e.g., montan wax) may be the carboxylic acids and esters,which may comprise as much as 90% of the wax. These chemical groups maybe converted into carboxylate moieties upon hydrolysis in a high pHenvironment (e.g., in an environment including aqueous KOH). Thecarboxylate moieties may act as a hydrophilic portion or “head” of themolecule. The hydrophilic portions can directly interface with thesurrounding aqueous environment, while the rest of the molecule, whichmay be a lipophilic portion or “tail”, may be embedded in the wax.

A stabilizer capable of hydrogen bonding to carboxylate moieties (e.g.,PVOH or ethylene-vinyl alcohol-vinyl acetate terpolymer as describedabove) may be used in the wax emulsion. The polar nature of thecarboxylate moiety may offer an optimal anchoring point for a stabilizerchain through hydrogen bonding. When stabilizer chains are firmlyanchored to the carboxylate moieties as described above, the stabilizermay provide emulsion stabilization through steric hindrance. Inembodiments where the wax emulsion is subsequently dispersed in awallboard (e.g., gypsum board) system, all the water may be evaporatedaway during wallboard manufacture. The stabilizer may then function as agate-keeper for repelling moisture. Decreasing the solubility of thestabilizer in water may improve the moisture resistance of the waxemulsion and the wallboard. For example, fully hydrolyzed PVOH may onlydissolve in heated, and not cool, water. For another example,ethylene-vinyl alcohol-vinyl acetate terpolymer may be even less watersoluble than PVOH. The ethylene repeating units may reduce the overallwater solubility. Other stabilizer materials are also possible. Forexample, polymers with hydrogen bonding capability such as thosecontaining specific functional groups, such as alcohols, amines, andthiols, may also be used. For another example, vinyl alcohol-vinylacetate-silyl ether terpolymer can be used. An example vinylalcohol-vinyl acetate-silyl ether terpolymer is Exceval R-2015,available from Kuraray Chemical Company. In some embodiments,combinations of stabilizers are used.

In some embodiments, the wax emulsion comprises a base. For example, thewax emulsion may comprise an alkali metal hydroxide, such as potassiumhydroxide or other suitable metallic hydroxide, such as aluminum,barium, calcium, lithium, magnesium, sodium and/or zinc hydroxide. Thesematerials may serve as saponifying agents. Non-metallic bases such asderivatives of ammonia as well as amines (e.g., diethanolamine ortriethanolamine) can also be used. Combinations of the above-mentionedmaterials are also possible. If included in the wax emulsion, potassiumhydroxide is preferably present in an amount of 0% to 1%, morepreferably about 0.1% to about 0.5% by weight of the wax emulsion.

In some embodiments, an exemplary wax emulsion comprises: about 30% toabout 60% by weight of water; about 0.1% to about 5% by weight of alignosulfonic acid or a salt thereof; about 0% to about 1% by weight ofpotassium hydroxide; about 30% to about 50% by weight of wax selectedfrom the group consisting of paraffin wax, slack wax and combinationsthereof; and about 0.1% to about 10% montan wax, and about 0.1 to 5% byweight of ethylene-vinyl alcohol-vinyl acetate terpolymer.

The wax emulsion may further include other additives, including withoutlimitation additional emulsifiers and stabilizers typically used in waxemulsions, flame retardants, lignocellulosic preserving agents,fungicides, insecticides, biocides, waxes, sizing agents, fillers,binders, additional adhesives and/or catalysts. Such additives arepreferably present in minor amounts and are provided in amounts whichwill not materially affect the resulting composite board properties.Preferably no more than 30% by weight, more preferably no more than 10%,and most preferably no more than 5% by weight of such additives arepresent in the wax emulsion.

Shown in the below tables are example embodiments of a wax emulsion,although other quantities in weight percent may be used.

TABLE 1 Raw Material Quantity in Weight Percent Water 58 Polyvinylalcohol 2.70 Dispersant (Optional) 1.50 Paraffin Wax 34.30 Montan Wax3.50 Biocide 0.02

TABLE 2 Raw Material Quantity in Weight Percent Water 58.80 Polyvinylalcohol 2.80 Diethanol Amine 0.04 Paraffin Wax 34.80 Montan Wax 3.50Biocide 0.10

The wax emulsion may be prepared using any acceptable techniques knownin the art or to be developed for formulating wax emulsions, forexample, the wax(es) are preferably heated to a molten state and blendedtogether (if blending is required). A hot aqueous solution is preparedwhich includes any additives such as emulsifiers, stabilizers, etc.,ethylene-vinyl alcohol-vinyl acetate terpolymer (if present), potassiumhydroxide (if present) and lignosulfonic acid or any salt thereof. Thewax is then metered together with the aqueous solution in appropriateproportions through a colloid mill or similar apparatus to form a waxemulsion, which may then be cooled to ambient conditions if desired. Insome embodiments, the improved wax emulsion may be incorporated with orcoated on various surfaces and substrates. For example, the improved waxemulsion may be mixed with gypsum to form a gypsum wallboard havingimproved moisture resistance properties.

In one embodiment, the wax components may be mixed in an appropriatemixer device. Then, the wax component mixture may be pumped to a colloidmill or homogenizer. In a separate step, water, and any emulsifiers,stabilizers, or additives (e.g., ethylene-vinyl alcohol-vinyl acetateterpolymer) are mixed. Then the aqueous solution is pumped into acolloid mill or homogenizer. These steps may be performedsimultaneously, or they may be performed at different times. Pumping ofthe wax component mixture and that of the aqueous solution may beperformed at the same time, so as to ensure proper formation of dropletsin the emulsion. In some embodiments, steps wax component mixing andpumping may be performed before mixing of the aqueous solution isstarted. Finally, the two mixtures are milled or homogenized to form anaqueous wax emulsion.

Some or all steps of the above method may be performed in open vessels.However, the homogenizer, if used, may use pressure in its application.

Advantageously in some embodiments, the emulsion, once formed, is cooledquickly. By cooling the emulsion quickly, agglomeration and coalescenceof the wax particles may be avoided.

In some embodiments the wax mixture and the aqueous solution arecombined in a pre-mix tank before they are pumped into the colloid millor homogenizer. In other embodiments, the wax mixture and the aqueoussolution may be combined for the first time in the colloid mill orhomogenizer. When the wax mixture and the aqueous solution are combinedin the colloid mill or homogenizer without first being combined in apre-mix tank, the two mixtures may advantageously be combined underequivalent or nearly equivalent pressure or flow rate to ensuresufficient mixing.

In some embodiments, once melted, the wax emulsion is quickly combinedwith the aqueous solution. While not wishing to be bound by any theory,this expedited combination may beneficially prevent oxidation of the waxmixture.

Water-Resistant Exterior Joint Compound

Embodiments of the disclosed wax emulsion can be used to form awater-resistant exterior joint compound. The joint compound can be usedto cover, smooth, or finish gaps in exterior sheathing wallboards, suchas joints between adjacent boards, screw holes, and nail holes. Thejoint compound can also be used for repairing surface defects onexterior walls and applying texture to exterior walls amongst numerousother applications. The exterior joint compound can also be speciallyformulated to serve as a cover coat on cement and concrete surfaces. Theexterior joint compound can be particularly useful in locations wherethere is high humidity, moisture and direct impact from rain, exteriorwater exposure during construction, and to prevent molding or otherdeleterious effects.

Wax emulsions can be particularly advantageous for use in a jointcompound as compared to, for example, the currently availablesilyl-terminated polyethers based compounds. The STPEs are expensive andare not water-based, which means an organic solvent must be employed tohandle those compounds. Because wax emulsions, such as those describedherein, can advantageously increase the adhesion properties of a jointcompound, and thus can be added at higher dosage levels.

Embodiments of the exterior joint compound can be applied in thin layersto a surface. The exterior joint compound can be applied by, forexample, using a trowel or other straight edged tool. However, theapplication and thickness of the layers of joint compounds is notlimiting. Further, multiple layers may be applied in order to obtain asmooth wall. The number or layers applied is not limiting. In someembodiments, each layer can be allowed to dry prior to application ofthe next layer. In some embodiments, a second layer can be applied whenthe first layer is only partially dried. In some embodiments, the jointcompound can be spread over mesh or tape used to connect wallboards. Insome embodiments, the joint compound may also be used to patch andtexture exterior sheathing walls. In some embodiments, the jointcompound can be made of water, preservative, calcium carbonate, mica,clay, thickener, binder (e.g., latex binder), and a wax emulsion. Inaddition to a latex binder, other water soluble binders, such aspolyvinyl alcohol, can be used as well. Other materials, such as talc,binders, fillers, thickening agents, preservatives, limestone, perlite,urea, defoaming agents, gypsum latex, glycol, and humectants can beincorporated into the exterior joint compound as well or can substitutefor certain ingredients (e.g., talc can be used in place of, or inaddition to mica; gypsum can be used in place of, or in addition tocalcium carbonate, etc.). In some embodiments, the calcium carbonate canbe replaced either wholly or partially with a surface micro-roughenedfiller that can further enhance the joint compound's hydrophobicity. Insome embodiments, Calcimatt™, manufactured by Omya AG, can be used. Insome embodiments, cristobalite (silicon dioxide) such as Sibelite® M300,manufactured by Quarzwekre, can be used. These fillers can be used aloneor in combination.

In some embodiments, the joint compound can be mixed in water. Thismixture can then be applied to a surface, e.g., hole or joint, and canbe allowed to dry. Once the water evaporates from the mixture, a dry,relatively hard cementitious material can remain. In one embodiment, thewall system can be made of a plurality of boards. There is no limit tothe amount of boards or the positioning of boards next to one another.Where two boards are adjacent to one another, a gap, or joint, can beformed. While the boards themselves may be water-resistant, the jointsmay allow for moisture to pass through. Therefore, embodiments of thewater-resistant joint compound can be spread across the joints. Thecompound can be spread on the joint to completely cover the joint. Insome embodiments, the boards can also contain holes. These holes can beformed by nailing the boards into studs, or other attachment means.Regardless of the reason for the hole, the compound can also be used tocover the holes. The compound can insert partial through the holes, orcan cover the top of the holes, or both. The compound can cover anyfastener, e.g. a screw or nail that is located in the hole. In someembodiments, the compound for covering and filling the hole are the samecompound. The application and thickness of the compounds on the boardsis not limiting, and common methods of application can be used.

An exemplary formula range of an embodiment of a water-resistantexterior joint compound using the above disclosed wax is shown in thebelow table:

TABLE 3 Component Range Water 15-40% Defoaming agent 0.0-0.5% Preservatives 0.1-1.0%  Calcium Carbonate 10-50% Siliconate  0-5% Mica 0-20% Attapulgite Clay  0-3% Perlite 0%-15% Wax emulsion 15-40% Latexbinder  1-10% Cellulose ether thickener 0.1%-3% 

In the above table, various components of an exemplary joint compoundwith the weight percent range of each component are provided. It isunderstood that the range for any component provided herein onlyreflects an abbreviation of the fact each internal weight percent numberfor a particular component is disclosed as if fully set forth herein.The specific intermediate weight percent numbers for any component aredisclosed at a 0.1 weight percent interval, as if they are fully setforth herein. So, for example, the cellulose ether thickener isdisclosed in the range of from about 0.1% to 3%. This means that thefollowing weight percent numbers for cellulose ether thickener are alsofull set forth herein: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4,2.5, 2.6, 2.7, 2.8, 2.9, 3.0,

In addition, for the cellulose ether thickener and for other componentsdisclosed herein, the specific component can be present in an amountthat is in a range defined by any two numbers disclosed by the aboveseries of numbers, including the end-points of such range. Thisdisclosure instruction applies to every component that is disclosed inthe present patent application.

Further, an example of a specific formulation for a water-resistantjoint compound can is shown in the below table, although other weightpercentages may be used:

TABLE 4 Component Weight in (g) Water 350 Defoaming agent 1 PreservativeActicide CBM2 2 Preservative Acticide CMKW2 11.6 Calcium Carbonate(Microwhite 100) 490 Potassium Siliconate 3.5 Mica 150 Attapulgite Clay(Attagel 30) 12 Expanded Perlite (SilCell 43-32) 50 AquaDri Wax Emulsion(81061) 350 Latex binder Acronal NX4787 40 Cellulose ether thickener 4.5(Methocel 240S) Total solids 866.6 Total weight 1464.6 % solids 59.17%

The contact angle of a surface coated with the above exterior jointcompound formulation was found to be 110, in other words, an hydrophobicsurface was generated. Also, the 2-hour Cobb value was found to be at 15g/m². The exterior sheathing wallboards have a permeance of 50-100 g/m².Compared to the exterior wall-boards (sheathing), therefore, the jointshave an improved Cobb value. Thus, the joints and holes will not be theweakest link in terms of moisture repellency and protection when thejoint compound of the present invention is used to seal the joints,gaps, and holes in the exterior surface on the sheathing walls duringconstruction.

The mold resistance, measured by ASTM G-21 for these exterior sheathingwallboards and the inventive exterior joint compound obtained a “pass”characterization.

The long-term weather resistance for both the exterior sheathingwallboard, and the inventive exterior joint compound was found to beexcellent. The exterior joint compound showed no wear with or withoutfabric reinforcement more than six months after exposure to outsideenvironment. Here, the exterior joint compound was coated on a sheathingwallboard. While the coating without fabric reinforcement showedhairline cracking in the joint (while fabric reinforcement eliminatesthe hairline crack), this particular type of crack does not factor inthe determination of the coating's weatherability because weatherabilityis confined to coating degradation due to UV, rain, and otherenvironmental conditions.

The wax emulsion used in the joint compound can be formed from slackwax, montan wax, paraffin wax, carnauba wax, tall oil, sunflower wax,rice wax, and any other natural or synthetic wax containing organicacids and/or esters, or waxes that have been described previously. Forexample, synthetic wax used in the joint compound may comprise ethylenicpolymers or hydrocarbon types, optionally derived via Fischer-Tropschsynthesis, or combinations thereof. By way of further example, syntheticwax used in the joint compound may comprise polyethylene glycol,methoxypolyethylene glycol, or combinations thereof. Optionally, thesynthetic waxes can be added in concentrations ranging from about 0.1%to about 8% of the dry weight of the joint compound or from about 0.5%to about 4.0% of the dry weight of the joint compound. In someembodiments, the wax emulsion is stabilized by polyvinyl alcohol.

In some embodiments, perlite can be used in the exterior joint compoundto, for example, control the density, shrinkage, and crack resistance ofthe joint compound. In some embodiments, perlite need not be used (e.g.,where weight is not as much of a factor).

In some embodiments, mica can be used in a compound as well. Mica, whichis a low bulk density mineral, may be used as a filler or extender, andmay also improve crack resistance of the joint compound.

In some embodiments of the exterior joint compound gypsum (calciumsulfate dihydrate) can also be used. Gypsum can be used to replacecalcium carbonate, or can be used in conjunction with calcium carbonate.In some embodiments, talc can be included in the exterior joint compoundto, for example, enhance application properties and can also be used asa white extender pigment.

In some embodiments, clay can be used in the exterior joint compound as,for example, a non-leveling agent and/or a thickening agent that cancontrol the viscosity or rheology of the final product. Clay can alsohelp enhance or create the water-holding properties of the jointcompound.

In some embodiments, thickeners can be used to control the viscosity,affect the rheology, and affect the water holding characteristics of theexterior joint compound. For example, cellulose ether can be used as athickener.

In some embodiments, binders can be used in the exterior joint compoundto, for example, improve bonding to the substrate such as wallboard.

In some embodiments, a glycol can be used in the exterior joint compoundto provide functional properties to the exterior joint compound such aswet edge, open time, controlling drying time, and freeze/thaw stability.

In some embodiments, other rheology modifiers can also be used inconjunction with, or instead of, some of the above describedcompositions.

In some embodiments, fillers can be used in the exterior joint compound.For example, calcium carbonate, calcium sulfate hemihydrate, or calciumsulfate dihydrate can all be used as fillers, though other materials canbe used as well. Further, thickeners, preservatives, binders, and otheradditives can be incorporated into the joint compound.

Other additives can also be added to the described exterior jointcompound in addition to the wax emulsion. In some embodiments, metalsiliconate salts such as, for example, potassium siliconate, as well assilicone based compounds such as, for example, poly hydrogen methylsiloxane and polydimethyl siloxane, could provide advantageous waterresistance to the exterior joint compound. In some embodiments,fluorinated compounds and stearate-based salts could also be used toprovide advantageous water resistance.

In some embodiments, the wax emulsion can be replaced by other materials(or used in combination with other materials) which may also increasethe water repellency of the exterior joint compound. For example, metalsiliconate salts such as, for example, potassium siliconate, as well assilicone based compounds such as, for example, poly hydrogen methylsiloxane and polydimethyl siloxane, could be used in place of the waxemulsion (or in combination with the wax emulsion). In some embodiments,fluorinated compounds and stearate-based salts could also be usedinstead of the wax emulsion or in combination with the wax emulsion. Thecompounds described in this paragraph can be used alone as a replacementfor wax emulsion, or can be used in combination with each other.

In some embodiments, the disclosed exterior joint compound can cover ajoint or hole and provide resistance to water penetration. Further, theexterior joint compound is formulated to properly adhere to any boardsthat the compound is placed onto. Further, the exterior joint compoundcan have adequate sag resistance, compatibility, and contact angle.

In some embodiments, the exterior joint compound can provide waterrepellency. One indication of water repellency is the contact angle of awater droplet on the surface of the dried joint compound. A waterdroplet surface that has a contact angle of less than 90 degrees wouldgenerally be considered hydrophilic (the smaller the contact angle thegreater the hydrophilicity). Conversely, surfaces that cause a waterdroplet to have a contact angle greater than 90 degrees are generallyconsidered hydrophobic. Commercially available ready mix joint compoundhave contact angles of about zero degrees, meaning that a drop of waterplaced on such a surface will rapidly spread and wet out on the surface.

Some embodiments of the disclosed exterior joint compound, containing awax emulsion, can have an average contact angle of about 98 degrees(based on an average of six measurements), or greater than about 98degrees, indicating a hydrophobic surface. This contact angle value canbe modified, higher or lower, by adjusting the dosage level of the waxemulsion in the exterior joint compound formula. In some embodiments,the contact angle can be between about 60 to about 150 degrees, or about60, about 70, about 80, about 90, about 100, or about 110 degrees. Insome embodiments, the joint compound can have a contact angle of greaterthan about 60, greater than about 70, greater than about 80, greaterthan about 90, or greater than about 100. In other words, the contactangle can be: 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73,74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91,92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107,108, 109, 110, 111, 112, 113, 14, 115, 116, 117, 118, 119, 120, 121,122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135,136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149,and 150.

In addition, the contact angle of the exterior joint compound is in arange defined by any two numbers disclosed by the above series ofnumbers, including the end-points of such range.

In some embodiments, the disclosed exterior joint compound can beresistant to seepage of water into itself. This attribute can begenerally determined by measuring the Cobb value of the compound. A Cobbvalue is a quantitative determination of how much water a substrateabsorbs in a predetermined timeframe per unit area, generally measuredas grams of water absorbed in 2 hours by a one square meter area. Forexample, a leveled surface of an embodiment of the disclosed exteriorjoint compound is applied on to a piece of commercially availableregular ½″ gypsum wallboard. A 100 cm² Cobb testing ring is then fittedon top of the joint compound and the ring filled with 100 grams of waterto begin the test. After two hours, the water is discarded and the Cobbring disassembled. The wallboard/joint compound combination is thenweighed to determine how much water is absorbed. This gram weight ofwater is multiplied by 100 to give the Cobb value of water absorbed persquare meter. Exterior sheathing wallboard (upon which the exteriorjoint compound is applied) has a Cobb value of less than 100 g/m². Theexterior joint compound of the present invention can be formulated tomatch the Cobb value of its substrate (the sheathing board), 100 g/m²and below. In some embodiments, the desired Cobb value can be obtainedby adjusting the composition of the wax emulsion and the siliconatecontent in the formulation, for example, potassium siliconate. In someembodiments, a 2-hr Cobb values is below about 100 g/m². Stated anotherway, the Cobb value of the exterior join compounds of the presentinvention can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55,56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73,74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91,92, 93, 94, 95, 96, 97, 98, 99, and 100.

In addition, in some embodiments, the Cobb value of the exterior jointcompound is in a range defined by any two numbers disclosed by the aboveseries of numbers, including the end-points of such range.

A metal ring of 2.5″ internal diameter (and ⅖″ internal height) isplaced on a silicone coated paper (for non-stick). A sample ofconventional ready-mixed interior joint compound used for interiorgypsum wallboards is then applied inside the ring such that it occupiesthe entire open volume of the ring. The conventional joint compound isallowed to dry on a lab bench overnight, then transferred into a forcedair oven at 50° C. where drying is continued for another 5 hours (untilconstant weight) to form a patty. The same procedure is performed withthe disclosed wax emulsion based exterior joint compound, forming asecond patty. The patties are then lightly sanded all around (to ensurepatty smoothness), weighed, and then submerged in a water bath in amanner similar to ASTM Method C473. To prevent sample flotation when inthe water, a 100 gram weight is placed on each sample through theduration of the test. As in ASTM C473, the joint compound patties areremoved from the water bath after 2 hours, excess water patted off, andweighed. The results of the testing are shown in the below table.

TABLE 5 Joint compound Sample condition Sheetrock Lightweight DustControl Broke apart Disclosed Joint Compound with 6.7% Wax Maintainedstructural and Emulsion dimensional integrity

While the commercial joint compound crumbles at the end of the test andcould not be reused or retested, the patty containing the disclosed waxemulsion exterior joint compound retains its structural and dimensionalintegrity. The patty containing the disclosed wax emulsion is in factdried and then re-submerged to repeat the test. In some embodiments, thewax emulsion joint compound can have a % water absorbance from about 4to about 6. In some embodiments, the wax emulsion joint compound canhave a % water absorbance of about 6 or less, about 5.4 or less, about5.2 or less, or about 4 or less. The structural and dimensionalintegrity of the wax emulsion containing patty remains intact andunchanged through the third testing cycle, suggesting that it cancontinue to survive multiple cycles of submersion and retesting. Bycontrast, the standard commercially available joint compound cannotsurvive a single test cycle. Standard interior joint compounds typicallyhave a pH of 8-9, primarily as a result of the high calcium carbonatecontent. However, it can be undesirable for the pH of joint compound tobe much higher than 9.0 because of the corrosive effects such high pHwould have on worker's finishing tools as well as on the skin.Advantageously, the wax emulsion used in embodiments of the disclosedexterior joint compound can have a pH of between 7.0 and 8.0, meaningthat adding it as a component in the exterior joint compound formulationdoes not result in an overall increase in the pH of the exterior jointcompound. This can advantageously be done without the addition of anacid. Accordingly, the pH of the joint compound can be about 7.0 orabout 8.0, or below about 9.0 or below about 8.0.

In some embodiments, the exterior joint compound may contain a biocidein an effective amount. In one embodiment, the biocide content rangefrom about 0.1% to about 5% by weight of the joint compound. In otherwords, the biocide content can be have the following content inpercentage weight: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4,2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8,3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0. The biocideweight content can also be in a range determined by any two of thesenumbers as endpoints, and including the endpoints. Exemplary biocidesmay include, without limitation silver-containing materials,gold-containing materials, aluminum-containing materials,copper-containing materials, fungicides, antimycotics, bactericides,viricides, carbamates, triclosan, or mixtures of the same. Commerciallyavailable fungicides include the Acticide® series from Thor Specialties,Inc., Shelton, Conn.; and the nuocide® series available fromInternational Specialty Products, Cranbury, N.J. Depending on the enduse of the exterior joint compound, the specific biocide used may betargeted to the organisms that are likely to be encountered in the enduse environment. For example, if the exterior joint compound is used ina residential or commercial building, the selected biocide(s) mayinclude a fungicide or other antimycotic. If the exterior joint compoundis used to seal the gaps between sheathing wallboard for a building thathouses a food processing or storage facility or medical facility, theselected biocide(s) may include bactericides and/or viricides.

The biocide should be present in the exterior joint compound must be inan amount sufficient to exhibit a level of microbe mitigating activitywhen such joint compound is applied to the sheathing wallboards. Asappreciated by one of ordinary skill in the art, such amount willnecessarily be variable depending on numerous factors, such as thenature and number of other components present in the joint compound, thespecific biocide(s) used, and the level of microbe mitigating activitydesired in the end product.

While the above detailed description has shown, described, and pointedout features as applied to various embodiments, it will be understoodthat various omissions, substitutions, and changes in the form anddetails of the devices or algorithms illustrated can be made withoutdeparting from the spirit of the disclosure. For example, certainpercentages and/or ratios of component ingredients have been describedwith respect to certain example embodiments; however, other percentagesand ratios may be used. Certain process have been described, howeverother embodiments may include fewer or additional states. As will berecognized, certain embodiments of the inventions described herein canbe embodied within a form that does not provide all of the advantages,features and benefits set forth herein, as some features can be used orpracticed separately from others.

What is claimed is:
 1. A water-resistant joint compound comprising:water; a defoaming agent; preservatives; calcium carbonate or gypsum ora combination thereof; mica or talc or a combination thereof;attapulgite clay; and wax emulsion, wherein the wax emulsion comprisesparaffin wax, montan wax, carnauba wax, sunflower wax, rice wax, tallowwax, a wax containing organic acids and/or esters, or an emulsifiercontaining a mixture of organic acids and/or esters, or synthetic wax,or combinations thereof.